Apparatus for withdrawing and advancing the casting in a continuous casting machine



May 16, 1967 E. A. oLssoN APPARATUS FOR WITHDRAWING AND ADVANCING THECASTING IN A CONTINUOUS CASTING MACHINE Filed Feb. 4, 1965 3Sheets-Sheet 1 V fivyf.

INVENTOR.

IIIIA May 16, 1967 E. A. OLSSON 3,319,699 APPARATUS FOR WITHDRAWING ANDADVANCING THE CASTING IN A CONTINUOUS CASTING MACHINE Filed Feb. 4, 19653 Sheets-Sheet 2 INVENTOR.

ERIK ALLAN OLSSON May 16, 1967 E. A. OLSSON 3,319,699

APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING Filed Feb. 4, 1965INVENTOR.

ERIK ALLAN OLSSON a I a ATTO United States Patent APPARATUS FORWITIIDRAWING AND ADVANC- ING THE CASTING IN A CONTINUOUS CASTING MACHINEErik Allan Olsson, Tagerhalde 6, 8700 Kusnacht, Zurich, SwitzerlandFiled Feb. 4-, 1965, Ser. No. 432,442 16 Claims. (Cl. 164-282) Thisapplication is a continuation-in-part of my application Serial No.152,259, filed November 14, 1961, now abandoned.

The invention relates to an apparatus for withdrawing and advancing andguiding the casting in a continuous casting machine in which the castingleaving an openended mold is engaged by rolls which are adapted towithdraw and advance the casting without subjecting it to a deformingmechanical working.

The degree of solidification of the casting when it leaves the mold isthe deciding factor as regards how far from its mouth the withdrawingrolls must be placed in order not to damage the casting by deformationthereof. The rolls must engage the casting with a pressure so great thatthe friction between the casting and the rolls is sufiicient to Withdrawthe casting from the mold and to support the weight of the casting sothat the casting does not move downwards in an uncontrollable manner.The weight of the casting depends on the sump depth, and the length ofcasting required below the sump point, i.e., the height of the rolls andthe cutting means and/or the bending means.

As disclosed inter alia in the Swedish Patent No. 164,526 internaldefects in the form of fissures extending at an angle to the rolls mayoccur as a result of a too high roll pressure. Naturally, the materialwithstands little or no deformation associated with tension stresses aslong as the temperature has not fallen sutliciently to result in anappreciable cohesion between the crystals. Some grades of steel havetheir ranges of red shortness which is well known from the rolling planttechnology. Since an equalization of temperature occurs very slowly iniron and steel, it is readily seen that a deformation, e.g. a wideningof the casting between the rolls, may result in cracks in some zones ofthe cross-section. Therefore, it is necessary that the cooling space,i.e., the distance between the mold and the rolls, is chosen so longthat the casting is solidified substantially through or at least hasobtained such a rigidity that the roll pressure necessary to provide therequired friction does not deform the casting to a detrimental extent.

To obviate this disadvantage the practice has been to reduce thestresses exerted by the rolls on the casting, this being usuallyachieved by making the rolls with as large diameters as possible.

It is also indisputable that at the same pressure the depth ofindentation or the linear pressure is reduced with an increasing rolldiameter, but on the other hand the widening increases. Since breaks inthe material at the temperature involved must depend on the materialflow and the distribution of the various stresses (shearing, compressionand tension stresses), it has been found in some cases that the wideningis more dangerous than the elongation and therefore a smaller rolldiameter is to be preferred.

The object of the present invention is to avoid the disadvantages ofknown machines and to provide a continuous casting machine in which therolls for withdrawing and advancing the casting can act upon the castingwhile a great portion of the cross-section is still fluid withoutdeforming the casting, whereby the rolls can be positioned closer to theoutlet of the mold so that the 3,319,599 Patented May 16, 1967 overallheight of the continuous casting machine can be considerably reduced,and also further reduce the height by deflecting the casting from avertical to a substantially horizontal direction of travel.

In accordance with the present invention this and other objects areachieved by a continuous casting machine, in which the roll assembly forwithdrawing and advancing the casting includes such a number of rollpairs, not less than three, arranged one behind the other in thedirection of movement of the casting that the contacting pressure ofeach roll pair on the casting can be kept low while the total frictionbetween the rolls of the roll assembly and the casting is sufiicient forwithdrawing and advancing the casting, even while a great portion of thecross-section of the metal is still fluid.

In a preferred embodiment of the invention the roll pairs in the rollassembly are adjustable relatively to each other in such a manner thatthe roll assembly simultaneously with its withdrawing and advancingaction, can bend the casting from a vertical to a horizontal orsubstantially horizontal direction of movement.

These and other features characteristic of this invention will beexplained more in detail below with reference to the embodimentillustrated on the accompanying drawings.

FIGURE 1 shows diagrammatically and in elevation a continuous castingmachine including a withdrawing and advancing apparatus in accordancewith this invention.

FIGURES 2 and 3 show the same machine in elevation and in end view,respectively, and with some parts broken away.

The continuous casting machine shown on the drawings comprises asupporting frame 1 which carries the pouring box 3 for supplying thecasting metal to a mold 9 provided on the frame, a device 2 provideddirectly below the mold 9 for cooling the casting and finally theapparatus for withdrawing and advancing the casting according to thisinvention. The latter apparatus comprises a plurality of roll pairs 4, 5arranged one behind the other and engaging the casting with a suitablepressure. Each roll pair is carried on a yoke-like supporting arm 7. Thearm 7 which is closest to the mouth of the mold is rigidly attached tothe frame while the other arms 7 are hingedly connected to each other insuch a way that the rolls, as seen in FIGURES 1 and 2, can eitherdischarge the casting vertically downward or also serve as means to bendand guide the casting from a vertical to a more or less horizontaldirection to facilitate its advancement to a straightening apparatus 8.In the embodiment illustrated, hydraulic or pneumatic cylinder-pistondevices 19 (FIG. 2) are utilized to adjust the supporting arms 7 inaccordance with the desired bending of the casting, and these devicesare capable of positioning the arms and their associated roll pairs tobend the casting either in a circular are or in a multiple radius curve,for example a curve whose radius decreases between successive rollpairs. This apparatus may be used to carry out the method disclosed inmy copending application Ser. No. 152,161, also filed Nov. 14, 1961.

The cooling zone which according to FIGURE 1 is rather long, can bereduced, depending on the casting speed, the size of the casting and thegrade of cast metal, sometimes even to a minimum where the withdrawingand advancing apparatus is situated more or less immediately below themold. Cooling of the casting can be provided, as needed, between therolls. Similarly supporting rollers or other means for supporting thecasting laterally can also be provided between the rolls to counteractits swelling due to the hydrostatic pressure which acts from theinterior of the casting.

On account of the bending of the casting by means of the rolls, thesemust of course be driven at different speeds on opposite sides of thecasting. This can be achieved in a variety of ways, but in a suitableembodiment the drive of each roll is achieved by hydraulic motors,whereby it will also be possible to vary the rotational speeds of therolls as desired, which is of particular importance if the bendingradius is to be changed, in which case it is also necessary to changethe rotational speed of the rolls at the same side of the casting.

By the'roll assembly of this invention which enables the casting to bebent already in the cooling zone, a considerable reduction of the heightof the total machine is achieved, as compared to known machines wherethe entire bending apparatus follows the drawing apparatus.

Due to the fact that the roll carrying arms 7 can be adjusted inter aliaso that the casting can pass through without bending, the advantage isgained that if for some reason a casting operation must be interruptedwith the casting still in the straight path, where it cools entirely,the cooled straight casting part can be removed from the machine withoutbending, since the rolls can be adjusted for straight vertical movement.Thus, the apparatus need not be constructed and dimensioned for bendinga cold rod, as would be necessary if the bending means could not be soadjusted. Similarly, the apparatus permits the use of a rigid startingbar which, when operation is to be started, is passed up through theapparatus to the bottom of the mold or a short distance thereabove toform a bottom closure therefor when pouring starts, and to serve as aconnecting piece between the casting formed in the mold and theapparatus of this invention before the casting itself is engaged by therolls. Of course, when the casting opeartion is interrupted a sufficientlength of the casting can be left in the machine to serve as a startingbar in the next operation.

When thin or narrow sections are cast, it may be suitable to build theadvancing and bending apparatus so long that the casting can bestraightened by the last pair or pairs of rolls so that a specialstraightening means need not be provided.

The invention is not restricted to the embodiment shown and described,which can be varied in many ways without departing from the spirit andscope of the invention. For example, the bending can be achieved by oneor more cylinders supported in a manner different from that shown on thedrawings. The use of spindles would also be possible. Embodiments inwhich some only of the rolls in the apparatus are driven are also withinthe scope of the invention.

I claim:

1. Apparatus for withdrawing and advancing the casting in a continuouscasting machine wherein the casting leaving an open-ended mold may havea molten interior comprising:

(a) at least three pair of opposed driven roll means positionedsuccessively in the direction of movement of the casting forfrictionally advancing and guiding the casting without altering thecross-sectional shape thereof,

(b) means for:

(1) independently adjusting the alignment of said pairs of rollsrelative to one another and relative to the direction in which thecasting leaves the mold and (2) successively bending the casting awayfrom the direction in which it leaves the mold to a direction at anangle thereto,

() each of said pairs of rolls being positioned along a non-circulararcuate path.

2. An apparatus as in claim 1, in which the casting leaves the mold in agenerally vertical direction, the roll pairs being positioned in spacedsuccession one below the other, said means for independently adjustingthe alignment being effective to shift the relativepositions of 4 theroll pairs laterally of the direction of travel of the casting so thatthe rolls in addition to withdrawing and advancing the casting, alsoselectively bend it from a generally vertical to a substantiallyhorizontal direction of movement.

3. Apparatus as in claim 2, in which the rolls of each roll pair aredriven by means of driving means such that the rotational speed of therolls is individually controllable.

4. An apparatus as in claim 2, in which each roll pair is attache-d to asupporting arm, said arms being hingedly connected to each other toachieve the desired bending of the casting.

5. An apparatus as in claim 4 in which the arms are joined together bymeans of links including cylinder-piston devices.

6. A guide for deflecting a continuous casting from its initial path oftravel to a path disposed at an angle thereto and then effecting astraightening thereof comprising a succession of opposed spaced elementsbetween which the casting is moved, and means to adjustably positioncertain of said elements relatively to others along the curved path inadvance of straightening to provide a curved path for the casting, whichcurved path is of successively different radii.

7. A guide for deflecting a continuous casting from its initial path toa path disposed at an angle thereto comprising a succession of opposedspaced elements between which the casting is moved, and means toadjustably position certain of said elements to provide a curved pathfor the casting, which path is of successively radii.

8. A guide as defined in claim'6 in which said opposed elements arerollers.

9. A guide as defined in claim 6 in which said opposed elements arerollers, at least some of said rollers being power-driven.

10. A guide as defined in claim 6 in which said 0p posed elements arerollers, at least some of said rollers being power-driven, each roll ofeach power-driven pair having an individual adjustable-speed drivethrough which the rolls of each pair may be driven at different speedsrelative to each other and to the rolls of other pairs.

11. In a continuous casting machine having an open ended mold with upperand lower ends, means centered in line with the lower end for receivinga casting formed in the mold and guiding it and supporting it, saidmeans comprising a fixed top frame with opposed rollers therein, asuccession of progressively lower frames each pivotally hung from theone above and each supporting a pair of opposed rollers similar to thefirst and movable from a position where the pairs of rollers define astraight path to a position where they define a curved path, and meansfor selectively adjusting the frames angularly relative to one anotherand holding them in adjusted position.

12. In a continuous casting machine having an openended mold with upperand lower ends, means centered in line with the lower end for receivinga casting formed in the mold and guiding it and supporting it, saidmeans comprising a series of supporting frames one below another, theuppermost frame being relatively fixed in a horizontal plane, means foradjustably supporting each succeeding frame selectively in a positionparallel with the first or at a predetermined angle relatively thereto,each frame having a pair of confronting rolls therein spaced from eachother and defining a guideway through which the casting emerging fromthe mold is supported.

13. A continuous casting apparatus as defined in claim 11 in which thesaid frames can be selectively adjusted to provide a straight passagefor the casting or one in which at least some of the frames define acurve of decreasing radius away from the mold.

14. A continuous casting apparatus as defined in claim 12 in which atleast some of the rollers of confronting pairs have means for drivingthem at relatively different peripheral speeds.

15. A guide for deflecting a continuous casting from its initialdirection of travel to a direction disposed at an angle thereto along acurved path comprising a plurality of opposed spaced elements betweenwhich the casting is moved and means for adjustably positioning certainof said elements relative to each other for varying the radius ofcurvature of said path along successive portions thereof.

16. A guide for deflecting a continuous casting from its initialdirection of travel to a direction disposed at an angle thereto along acurved path comprising a plurality of opposed spaced rolls between whichthe casting is moved means for adjustably positioning certain of saidopposed rolls relative to each other for varying the radius of curvatureof said path along successive portions thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,264,289 12/1941Betterton et a1. 2257.2 2,284,503 5/ 1942 Williams 22-57.2 2,698,467 1/1955 Tarquinee et al 2257.2 2,947,075 8/ 1960 Schneckenburger et a1.2257.2

J. SPENCER OVER'HOLSER, Primary Examiner. R. A. SANDLER, AssistantExaminer.

1. APPARATUS FOR WITHDRAWING AND ADVANCING THE CASTING IN A CONTINUOUSCASTING MACHINE WHEREIN THE CASTING LEAVING AN OPEN-ENDED MOLD MAY HAVEA MOLTEN INTERIOR COMPRISING: (A) AT LEAST THREE PAIR OF OPPOSED DRIVENROLL MEANS POSITIONED SUCCESSIVELY IN THE DIRECTION OF MOVEMENT OF THECASTING WITHOUT ALTERING THE CROSS-SECTIONAL SHAPE THE CASTING WITHOUTALTERING THE CROSS-SECTIONAL SHAPE THEREOF, (B) MEANS FOR: (1)INDEPENDENTLY ADJUSTING THE ALIGNMENT OF SAID PAIRS OF ROLLS RELATIVE TOONE ANOTHER AND RELATIVE TO THE DIRECTION IN WHICH THE CASTING LEAVESTHE MOLD AND